<!DOCTYPE html>

<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>id选择器</title>
        <style type="text/css">
            .wrapper { border: 1px solid blue ; }
            #first { background-color: yellow ; }
            #second { background-color: #dedede ;  }
        </style>
    </head>
    <body>

        <div class="wrapper" id="first">
            <form action="http://www.baidu.com/s" target="_blank">
                <input type="text" name="wd" id="wd" >
                <input type="submit" value="百度一下" id="button-baidu" >
            </form>
        </div>

        <div class="wrapper" id="second">
            <form action="http://www.so.com/s" target="_blank">
                <input type="text" name="q" id="q" >
                <input type="submit" value="360搜索" id="button-360" >
            </form>
        </div>

    </body>
</html>